1. Field of the Invention
The invention relates to a paste unit for a bottom buide device for star seal bottom bags having a glue reservoir or clue source, a metering roller in contact with the clue reservoir or glue source, a glue application roller which may be in contact with the glue reservoir or glue source, a making roller in contact with the glue application roller for transferring glue from the application roller to the bottom warps or the star seal bottoms, and drive mechanisms assigned to the above mentioned rollers.
2. Description of the Related Art
In a paste unit of a bottom guide device, glue is applied to the reared end, or the reared ends, and the thereby formed corner wraps of a tube section made of paper, plastic, or another suitable material, in order to subsequently achieve a permanently glued bag bottom by means of placing the reared ends onto the corner wraps.
A typically utilized paste unit of a bottom guide device is, for example, illustrated in patent specification DE 196 34 594 O2. A metering roller and a glue application roller are supported in a base plate, which together form a closed system in a body, in which a glue column of desired height is held. The glue is transferred to the printing roller from the glue application roller, whereas the amount of glue to be transferred is adjusted by the suitable selection of the distance between the metering roller and the glue applicatin roller. The printing roller transfers the glue to the workpiece to be glued. The closed system offers the advantage that the glue is applied evenly, and that the metering can be adjusted in very sensitive settings. Furthermore, no glue can be spread to the environment of the paste unit, which would cause contamination, as well as unnecessary glue consumption.
An open system is used in other known paste units. Principally, they are the same paste units as previously described, but instead of a body serving as the glue reservoir, a nozzle is merely used as the glue source. This nozzle is attached on the side of the gap between the metering roller and the glue application roller opposite of the printing roller. In such a paste unit, the rollers must be arranged vertically, whereas the nozzle applies the glue at the upper end of the metering roller on its exterior circumference. By means of gravitation and the rotation of the metering roller, the glue is distributed across the entire surface. The glue is fed from the metering roller across the glue application roller, and the printing roller is fed to the workpiece. The open system is said to have benefits with the use of certain types of glue. Due to the short duration of the glue in an open system—the use of this system leads to high losses of glue—the same can supply only a small amount of a solvent, and is therefore not prone to drying on.